WO2020138121A1 - Coating film forming composition and substrate manufacturing method - Google Patents

Abstract

The purpose of the present invention is to provide a coating film forming composition having excellent storage stability and a method for producing a substrate. The present invention provides a coating film-forming composition including a cobalt-containing compound having no cobalt-carbon bond and a solvent.

Description

Coating film forming composition and substrate manufacturing method

The present invention relates to a coating film forming composition and a method for producing a substrate.

In the production of semiconductor devices, a method of forming a cobalt-containing film on a substrate by chemical vapor deposition (CVD) and atomic layer deposition (ALD) using an organometallic precursor is used (WO 2011/017068). No.).

International Publication No. 2011/017068

The organometallic precursor used in the above conventional method for forming a cobalt-containing film has insufficient storage stability. Further, it takes a long time to form a cobalt-containing film having a film thickness of several tens of nm by CVD or ALD, and the productivity is low.

The present invention has been made based on the above circumstances, and an object thereof is to provide a coating film forming composition having excellent storage stability and a method for producing a substrate.

The invention made to solve the above problems is a cobalt-containing compound having no cobalt-carbon bond (hereinafter, also referred to as "[A] compound") and a solvent (hereinafter, also referred to as "[B] solvent"). A coating film-forming composition containing and.

Another invention made to solve the above problems comprises a step of directly or indirectly applying a composition to a substrate, wherein the composition comprises a cobalt-containing compound having no cobalt-carbon bond, a solvent, and a solvent. Is a method of manufacturing a substrate containing.

The coating film forming composition of the present invention has excellent storage stability. According to the method for producing a substrate of the present invention, by using the coating film forming composition, a cobalt-containing film having excellent conductivity and embedding property can be formed. Therefore, these can be suitably used in forming a cobalt-containing film in the fields of semiconductors, battery materials, antistatic fields, touch panel sensors and the like.

<Coating film forming composition>
The coating film forming composition contains the compound [A] and the solvent [B]. The coating film forming composition may contain optional components as long as the effects of the present invention are not impaired.

The coating film forming composition is used in the pattern forming method described later. Therefore, the coating film forming composition can be suitably used as a pattern forming composition.

The coating film forming composition is used in the inversion pattern forming method described later. Therefore, the coating film forming composition can be preferably used as a composition for forming a reverse pattern.

Hereinafter, each component contained in the coating film forming composition will be described.

[[A] compound]
The compound [A] is a cobalt-containing compound having no cobalt-carbon bond. The coating film forming composition may contain two or more kinds of [A] compounds. "Cobalt-containing compound" refers to a compound containing a cobalt atom. The “cobalt-carbon bond” refers to a covalent bond or a coordinate bond between a cobalt atom and a carbon atom which a cobalt carbonyl complex, a cobalt cyano complex, a cobalt ene complex, a cobalt-alkyl complex, a cobalt-acyl complex or the like has. The coating film forming composition has excellent storage stability by using a compound having no cobalt-carbon bond as the [A] compound.

The compound [A] has one or more cobalt atoms. In addition, examples of the valence of the cobalt atom in the compound [A] include 0 valence, 1 valence, 2 valence, and 3 valence. Of these, divalent or trivalent is preferable from the viewpoint of further improving storage stability.

Examples of the [A] compound include a cobalt salt, a complex having cobalt and a ligand, a combination thereof, and the like.

Examples of the cobalt salt include nitrates, sulfates, phosphates, carboxylates, perchlorates, carbonates, oxoacid salts such as borate, thiocyanates, sulfamate, fluorides, chlorides, Examples thereof include halides such as bromide and iodide, and hydroxides. Examples of the carboxylate include acetate, stearate, naphthenate, citrate, oxalate, succinate and the like. Among these, oxo acid salts are preferable, and nitrates, sulfates or carboxylates are more preferable, from the viewpoint of further improving storage stability.

Examples of the ligand that constitutes the complex include a monodentate ligand and a polydentate ligand.

Examples of the monodentate ligand include a hydroxo ligand, an amide ligand, a halogen ligand, an alkoxy ligand, an acyloxy ligand, a phosphine ligand, an amine ligand, and an ammonia ligand. To be

Examples of the amide ligand include an unsubstituted amide ligand (NH ₂ ), a methylamide ligand (NHCH ₃ ), a dimethylamide ligand (N(CH ₃ ) ₂ ), and a diethylamide ligand (N(C ₂ H _{5) 2),} dipropyl amido ligand _{(N (C 3 H 7)} 2) , and the like.

Examples of the halogen ligand include a fluorine ligand, a chlorine ligand, a bromine ligand, an iodine ligand and the like.

Examples of the alkoxy ligand include methoxy ligand, ethoxy ligand, propoxy ligand, butoxy ligand and the like.

Examples of the acyloxy ligand include acetoxy ligand, ethylyloxy ligand, butyryloxy ligand, t-butyryloxy ligand, t-amylyloxy ligand, n-hexanecarbonyloxy ligand, and n-octane. Carbonyloxy ligands and the like can be mentioned.

Examples of amine ligands include methylamine ligand, dimethylamine ligand, piperidine ligand, morpholine ligand, pyridine ligand and the like.

Examples of the phosphine ligand include trimethylphosphine ligand, triethylphosphine ligand, tributylphosphine ligand, triphenylphosphine ligand and the like.

Examples of the polydentate ligand include an oxygen bidentate ligand, a nitrogen bidentate ligand, a nitrogen tridentate ligand, a nitrogen tetradentate ligand, a nitrogen bidentate oxygen bidentate ligand, and a nitrogen bidentate. An oxygen tetradentate ligand, a phosphorus bidentate ligand, etc. are mentioned.

Examples of the oxygen bidentate ligand include a dicarboxylic acid-derived ligand, a hydroxy acid ester-derived ligand, a β-diketone-derived ligand, a β-ketoester-derived ligand, and a β-dicarboxylic acid ester. Examples thereof include a ligand derived from catechol and a ligand derived from catechol or a substitution product thereof.

Examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid and the like.

Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, salicylic acid ester and the like.

Examples of β-diketones include 2,4-pentanedione, 3-methyl-2,4-pentanedione, 3-ethyl-2,4-pentanedione and the like.

Examples of β-ketoesters include acetoacetic acid ester, α-alkyl-substituted acetoacetic acid ester, β-ketopentanoic acid ester, benzoylacetic acid ester, and 1,3-acetonedicarboxylic acid ester.

Examples of the β-dicarboxylic acid ester include malonic acid diester, α-alkyl-substituted malonic acid diester, α-cycloalkyl-substituted malonic acid diester, α-aryl-substituted malonic acid diester and the like.

As the nitrogen bidentate ligand, for example, a ligand derived from 2,2′-bipyridyl or a substituted product thereof, a ligand derived from 1,8-naphthyridine or a substituted product thereof, 2-(1H-pyrazole-1- Il) pyridine or a ligand derived from a substituted product thereof, 1,10-phenanthroline or a ligand derived from a substituted product thereof, ethylenediamine, propanediamine or butanediamine or a ligand derived from a substituted product thereof.

The tridentate nitrogen ligand includes, for example, a ligand derived from 2,6-di(1H-pyrazol-1-yl)pyridine or a substituted product thereof, and a ligand derived from α,α′,α″-tripyridyl or a substituted product thereof. Examples thereof include a ligand, a ligand derived from diethylenetriamine or a substituted product thereof, and a ligand derived from 1,4,7-triazacyclononane or a substituted product thereof.

As the nitrogen tetradentate ligand, for example, a ligand derived from phthalocyanine or a substituted product thereof, a ligand derived from naphthalocyanine or a substituted product thereof, a ligand derived from porphyrin or a substituted product thereof, a porphycene or a substituted product thereof , A ligand derived from triethylenetetramine or a substituted derivative thereof, a ligand derived from 1,4,7,10-tetraazacyclododecane or a substituted derivative thereof, 1,4,8,11-tetraaza Examples thereof include a ligand derived from cyclotetradecane or a substituted product thereof, a ligand derived from tris(2-aminoethyl)amine or a substituted product thereof, and the like.

As the nitrogen bidentate oxygen bidentate ligand, for example, a ligand derived from N,N′-bis(salicylidene)ethylenediamine or a substitution product thereof, N,N′-bis(3-hydroxy-2-butenylidene)ethylenediamine or Examples include ligands derived from the substitution products.

The nitrogen bidentate oxygen tetradentate ligand includes, for example, a ligand derived from ethylenediaminetetraacetic acid.

Examples of the phosphorus bidentate ligand include 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, and 2,2′. Examples thereof include diphosphine ligands such as -bis(diphenylphosphino)-1,1'-binaphthyl and 1,1'-bis(diphenylphosphino)ferrocene.

The lower limit of the content ratio of the [A] compound is preferably 30% by mass, more preferably 50% by mass, and 60% by mass with respect to all components other than the solvent [B] in the coating film forming composition. More preferable. The content ratio may be 100% by mass.

The lower limit of the content ratio of the [A] compound in the coating film forming composition is preferably 1% by mass, more preferably 5% by mass, further preferably 10% by mass, and particularly preferably 15% by mass. The upper limit of the content ratio is preferably 70% by mass, more preferably 50% by mass, further preferably 30% by mass, and particularly preferably 25% by mass.

[[B] solvent]
The solvent [B] can be used without particular limitation as long as it can dissolve or disperse the compound [A] and optional components contained as necessary. As the solvent [B], one type can be used alone, or two or more types can be used in combination.

Examples of the [B] solvent include organic solvents (hereinafter, also referred to as “[b] organic solvent”), water and the like. "Organic solvent" refers to an organic compound that is liquid at 25°C. When the [B] solvent contains the [b] organic solvent, the lower limit of the content ratio of the [b] organic solvent in the [B] solvent is preferably 20% by mass, more preferably 50% by mass, and further preferably 70% by mass. 90 mass% is especially preferable. The content ratio of the [b] organic solvent in the [B] solvent may be 100% by mass.

Examples of the organic solvent [b] include alcohol solvents, ketone solvents, ether solvents, ester solvents, nitrogen-containing solvents and the like. The organic solvent [b] can be used alone or in combination of two or more.

Examples of the alcohol solvent include monoalcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol and n-butyl alcohol, ethylene glycol, 1,2-propanediol, 1,2-butanediol, triethanolamine and diethylene glycol. , Polyhydric alcohols such as glycerin, polyhydric alcohol partial ethers such as propylene glycol monomethyl ether and propylene glycol monoethyl ether, lactate esters such as ethyl lactate and butyl lactate, 2-hydrazinoethanol, 3-hydrazinopropanol And the like, and hydroxyketone hydrazones such as 1-hydroxy-2-propanone hydrazone and 1-hydroxy-2-butanone hydrazone.

Examples of ketone solvents include chain ketones such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ketones such as cyclohexanone.

Examples of ether solvents include chain ethers such as n-butyl ether and cyclic ethers such as tetrahydrofuran and 1,4-dioxane.

Examples of ester solvents include carbonates such as diethyl carbonate, acetic acid esters such as methyl acetate and ethyl acetate, lactones such as γ-butyrolactone, and polyhydric alcohol partial ethers such as diethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate. Examples thereof include carboxylates.

Examples of the nitrogen-containing solvent include chain nitrogen-containing compounds such as N,N-dimethylacetamide and cyclic nitrogen-containing compounds such as N-methylpyrrolidone.

The [b] organic solvent preferably contains an alcohol solvent. As the alcohol solvent, monoalcohols, polyhydric alcohol partial ethers, lactic acid esters, hydrazide alcohols or hydroxyketone hydrazones are preferable. When the organic solvent [b] contains an alcohol solvent, the conductivity and embedding property of the cobalt-containing film formed from the coating film forming composition can be further improved. [B] When the organic solvent contains an alcohol-based solvent, the cobalt atom in the coating film is reduced by the alcohol-based solvent in the heating step of the coating film to become zero-valent, and the conductivity of the cobalt-containing film is improved. It is thought that. When the [b] organic solvent contains an alcohol solvent, the lower limit of the content ratio of the alcohol solvent in the [b] organic solvent is preferably 1% by mass, more preferably 10% by mass, further preferably 50% by mass, 80% by weight is particularly preferred. The content ratio of the alcohol solvent in the organic solvent [b] may be 100% by mass.

When the [B] solvent contains water, the upper limit of the water content in the [B] solvent is preferably 50% by mass, more preferably 40% by mass, and further preferably 30% by mass. The lower limit of the water content is, for example, 0.01% by mass.

The lower limit of the content ratio of the [B] solvent in the coating film forming composition is preferably 30% by mass, more preferably 50% by mass, further preferably 60% by mass, particularly preferably 70% by mass, and 75% by mass. % Is even more particularly preferred. The upper limit of the content is preferably 99% by mass, more preferably 95% by mass, further preferably 90% by mass, and particularly preferably 85% by mass.

The lower limit of the content of the [B] solvent is preferably 50 parts by mass, more preferably 100 parts by mass, further preferably 200 parts by mass, and particularly preferably 300 parts by mass with respect to 100 parts by mass of the [A] compound. The upper limit of the content is preferably 10,000 parts by mass, more preferably 2,000 parts by mass, further preferably 1,000 parts by mass, and particularly preferably 500 parts by mass.

By setting the content ratio or content of the solvent [B] within the above range, the storage stability of the coating film forming composition can be further improved.

[Arbitrary ingredients]
The composition for forming a coating film, as an optional component, an organic compound other than [B] solvent (hereinafter, also referred to as “[C] other organic compound”), a metal-containing compound other than [A] compound (hereinafter, (Also referred to as "other metal-containing compound") and the like. These optional components may be used alone or in combination of two or more.

([C] Other organic compound)
[C] Other organic compounds include, for example, compounds having an alcoholic hydroxyl group, compounds having a phenolic hydroxyl group, nitrogen-containing compounds, oxalic acid and the like. [C] When the above compound is used as the other organic compound, the conductivity and embedding property of the cobalt-containing film formed from the coating film forming composition can be further improved.

Examples of the compound having an alcoholic hydroxyl group include a compound having a plurality of alcoholic hydroxyl groups, a hydroxy acid or a salt thereof, a sugar compound and the like.

Examples of the compound having a plurality of alcoholic hydroxyl groups include ascorbic acid or a salt thereof, erythorbic acid or a salt thereof, trimethylolpropane, diethanolamine, pentaerythritol, dipentaerythritol, adamantanediol, adamantanetriol, adamantanetetraol, 1,3 -Dimethyl adamantane-5,7-diol, polyethylene glycol, polyvinyl alcohol and the like can be mentioned.

Examples of the hydroxy acid include glycolic acid, lactic acid, 3-hydroxypropionic acid, glyceric acid, tartronic acid, malic acid, tartaric acid, citric acid, 10-hydroxydecanoic acid, tropic acid and benzylic acid.

Examples of sugar compounds include erythritol, mesoerythritol, ribitol, xylitol, sorbitol, maltitol, glucose, fructose, lactose, arabinose, galactose, sucrose, maltose, trehalose, gluconic acid and glyceraldehyde.

Examples of the compound having a phenolic hydroxyl group include gallic acid or its salt or its ester, salicylic acid or its salt or its ester, tocopherol or its derivative, 2,6-di-t-butyl-4-methylphenol, t-butyl- Examples thereof include methoxyphenol, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, 1,2,4-trihydroxybenzene, dihydroxynaphthalene, rosmarinic acid, tannic acid, caffeic acid, dihydrocaffeic acid and quercetin.

Examples of the nitrogen-containing compound include formic acid hydrazide, acetic acid hydrazide, cyanoacetic acid hydrazide, trifluoroacetic acid hydrazide, propionic acid hydrazide, cyclohexanecarboxylic acid hydrazide, benzoic acid hydrazide, p-toluic acid hydrazide, salicylic acid hydrazide, 3-hydroxy-2-hydroxide. Naphthoic acid hydrazide, p-hydroxybenzoic acid hydrazide, 2-ethoxybenzoic acid hydrazide, succinic acid dihydrazide, maleic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, benzohydrazides, etc. Examples include hydrazones such as 9-fluorenone hydrazone, anthraquinone monohydrazone and salicylaldehyde hydrazone, and hydrazine derivatives such as methyl carbazate, ethyl carbazate, t-butyl carbazate and benzyl carbazate. ..

(Other metal-containing compounds)
As other metal-containing compounds, compounds other than cobalt, such as compounds containing nickel, iron, ruthenium, copper, silver, gold, palladium, platinum, zinc, aluminum, tin, tungsten, zirconium, titanium, tantalum, molybdenum, etc. Are listed. The other metal-containing compound may be a metal salt or a complex having a metal and a ligand.

When the coating film forming composition contains another metal-containing compound, the lower limit of the content ratio of the [A] compound in the entire metal containing compound contained in the coating film forming composition is 50 mass. %, more preferably 70% by mass, further preferably 90% by mass, particularly preferably 99% by mass. The content ratio of the [A] compound in the whole metal-containing compound contained in the coating film forming composition may be 100% by mass.

[Method for preparing coating film forming composition]
The coating film-forming composition is prepared by mixing the [A] compound, the [B] solvent and, if necessary, optional components in a predetermined ratio, and preferably using the obtained mixture with a filter having a pore size of 0.2 μm or less. It can be prepared by filtration.

<Substrate manufacturing method>
The method for manufacturing the substrate includes a step of applying the composition directly or indirectly to the substrate (hereinafter, also referred to as "application step"). In the method for producing a substrate, the composition described above as the composition for forming a coating film (hereinafter, also referred to as “composition (I)”) is used as the composition.

According to the method for manufacturing the substrate, a cobalt-containing film having excellent conductivity and embeddability can be formed by using the coating film forming composition described above.

The method for manufacturing the substrate may further include a step of heating the coating film formed by the coating step (hereinafter, also referred to as “heating step”) after the coating step.

The following describes each step included in the method for manufacturing the board.

[Coating process]
In this step, the composition (I) is applied directly or indirectly to the substrate. By this step, the coating film is directly or indirectly formed on the substrate. The above-mentioned coating method is not particularly limited and can be carried out by an appropriate method such as spin coating, cast coating, roll coating and the like. The case where the composition (I) is indirectly applied to the substrate includes, for example, the case where the surface-modified film of the substrate is formed on the substrate. The surface modification film of the substrate is, for example, a film having a contact angle with water different from that of the coating film.

The substrate may be, for example, a metal substrate or a silicon wafer. The “metal substrate” refers to a substrate containing metal atoms in at least a part of its surface layer. The metal atom contained in the metal substrate is not particularly limited as long as it is an atom of a metal element. Silicon and boron are not included in the metal atom. Examples of the metal atom include copper, iron, zinc, cobalt, aluminum, tin, tungsten, zirconium, titanium, tantalum, germanium, molybdenum, ruthenium, gold, silver, platinum, palladium, nickel and the like. Examples of the metal substrate include a metal substrate and a metal-coated silicon wafer. A silicon nitride film, an alumina film, a silicon dioxide film, a tantalum nitride film, a titanium nitride film, or the like may be formed on a part of the metal substrate.

The substrate may be a substrate on which no pattern is formed or a substrate on which a pattern is formed.

As the pattern of the substrate on which the pattern is formed, for example, the line width of the space portion is 2,000 nm or less, 1,000 nm or less, 500 nm or less, and further a line and space pattern or trench pattern of 50 nm or less, or a diameter of 300 nm or less, Examples of the hole pattern include 150 nm or less, 100 nm or less, and further 50 nm or less.

The dimensions of the pattern formed on the substrate are, for example, height of 100 nm or more, 200 nm or more, further 300 nm or more, width of 50 nm or less, 40 nm or less, further 30 nm or less, aspect ratio (pattern height/pattern width) However, a fine pattern of 3 or more, 5 or more, and further 10 or more can be used.

When a substrate on which a pattern is formed is used as the substrate, it is preferable that the coating film formed by applying the composition for forming a coating film on the substrate fills the concave portion of the pattern. For example, when the substrate on which the pattern is formed is a substrate on which the pattern of the silicon dioxide film is formed on a part of the metal substrate, the coating film fills the concave portion of the pattern to form the conductive circuit. can do.

[Heating process]
This step is an optional step of heating the coating film formed by the above coating step. It is considered that this step improves the conductivity of the coating film. It is considered that by heating the coating film, the cobalt atoms in the coating film are reduced to zero valence, and the conductivity of the cobalt-containing film is improved.

The atmosphere for heating the coating film may be a nitrogen atmosphere, a hydrogen atmosphere, an atmosphere, or the like. It is considered that when the coating film is heated in a hydrogen atmosphere, the reduction of cobalt atoms in the coating film is further promoted and the conductivity of the cobalt-containing film is further improved. The lower limit of the heating temperature is preferably 200°C, more preferably 300°C, and even more preferably 400°C. The upper limit of the temperature is preferably 700°C, more preferably 600°C, and even more preferably 550°C. The lower limit of the heating time is preferably 10 seconds, more preferably 60 seconds, and even more preferably 180 seconds. The upper limit of the above time is preferably 3,000 seconds, more preferably 1,200 seconds, and even more preferably 600 seconds.

Before heating the coating film, it may be preheated at a temperature of 60°C or higher and 150°C or lower. The lower limit of the time for preheating is preferably 10 seconds, more preferably 30 seconds. The upper limit of the time is preferably 300 seconds, more preferably 180 seconds.

-Exposure and heating can be combined in the method of manufacturing the substrate. The radiation used for this exposure is appropriately selected from visible rays, ultraviolet rays, far ultraviolet rays, electromagnetic waves such as X-rays and γ rays, and particle beams such as electron beams, molecular beams and ion beams.

The lower limit of the average thickness of the formed cobalt-containing film is preferably 1 nm, more preferably 10 nm, further preferably 30 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm, even more preferably 300 nm.

<Pattern forming method>
The pattern forming method includes a step of directly or indirectly coating the composition (I) on a substrate and an organic resist film directly or indirectly on the resist underlayer film formed by the coating film forming composition coating step. A step of applying a forming composition, a step of exposing the organic resist film formed by the organic resist film forming composition applying step to radiation, and a step of developing the exposed organic resist film, Using the organic resist pattern formed by the developing step as a mask, a step of contacting chlorine gas with the resist underlayer film, and a step of removing the resist underlayer film in contact with chlorine gas with a removing liquid containing water or an organic solvent are provided. ..

Specifically, the pattern forming method includes a step of applying the composition (I) described above to a substrate (hereinafter, also referred to as “application step (I-1)”), and a coating step (I -1) applying a composition for forming an organic resist film to the resist underlayer film formed (hereinafter, also referred to as "coating step (I-2)") and the above coating step (I-2 ) A step of exposing the organic resist film formed by radiation to radiation (hereinafter, also referred to as “exposure step”); a step of developing the exposed organic resist film (hereinafter, also referred to as “developing step”); Using the organic resist pattern formed by the development process as a mask, a step of bringing chlorine gas into contact with the resist underlayer film (hereinafter, also referred to as "chlorine gas contacting step"), and contacting chlorine gas with a removing solution containing water or an organic solvent The step of removing the resist underlayer film (hereinafter, also referred to as “removal step”) is provided.

The pattern forming method includes a step of directly or indirectly forming an organic underlayer film on the substrate (hereinafter, also referred to as “organic underlayer film forming step (I)”) before the coating step (I-1). Further provisions can be made. The pattern forming method optionally includes a step of forming a silicon-containing film on the resist underlayer film formed in the coating step (I-1) before the coating step (I-2). May be.

According to the pattern forming method, since the composition (I) is used, a good pattern can be formed.

Hereinafter, each step included in the pattern forming method will be described.

[Organic Underlayer Film Forming Step (I)]
In this step, an organic underlayer film is formed on the substrate. Examples of the organic underlayer film include the same as the organic underlayer film formed by the inversion pattern forming method described later.

[Coating process (I-1)]
In this step, the composition (I) is applied directly or indirectly to the substrate. By this step, a resist underlayer film is formed. Examples of the case where the composition (I) is indirectly applied to the substrate include a case where the composition (I) is applied to the organic underlayer film formed in the above organic underlayer film forming step (I). In this case, the resist underlayer film is formed on the organic underlayer film. This step is the same as the coating step in the above-described substrate manufacturing method.

[Silicon-containing film forming step]
In this step, a silicon-containing film is formed on the resist underlayer film formed in the coating step (I-1).

The silicon-containing film is usually formed by applying a composition for forming a silicon-containing film to the resist underlayer film, and then curing the coating film by exposing and/or heating. As the commercially available product of the above silicon-containing film forming composition, for example, "NFC SOG01", "NFC SOG04", "NFC SOG080", etc. of JSR Corporation can be used.

Examples of the radiation used for the above-mentioned exposure include electromagnetic waves such as visible light rays, ultraviolet rays, far ultraviolet rays, X-rays and γ rays, and particle beams such as electron beams, molecular beams and ion beams.

The lower limit of the temperature for heating the coating film is preferably 90°C, more preferably 150°C, and even more preferably 180°C. As the upper limit of the temperature, 550° C. is preferable, 450° C. is more preferable, and 300° C. is further preferable.

[Coating process (I-2)]
In this step, the composition for forming an organic resist film is applied to the resist underlayer film formed in the above coating step (I-1). When the silicon-containing film forming step is performed, the organic resist film-forming composition is applied to the silicon-containing film. Through this step, the organic resist film is formed.

In this step, specifically, by coating the composition for forming an organic resist film so that the resulting organic resist film has a predetermined thickness, and then heating to evaporate the solvent in the coating film. Forming an organic resist film.

Examples of the organic resist film-forming composition include a positive or negative chemically amplified resist composition containing a radiation-sensitive acid generator, and a positive resist composition containing an alkali-soluble resin and a quinonediazide-based photosensitizer. And a negative resist composition containing an alkali-soluble resin and a crosslinking agent.

The composition for forming an organic resist film is generally provided for forming an organic resist film by filtering with a filter having a pore size of 0.2 μm or less. In this step, a commercially available organic resist composition can be used as it is.

The method of applying the composition for forming an organic resist film is not particularly limited, and examples thereof include a spin coating method. The heating temperature is appropriately adjusted depending on the type of the organic resist film forming composition used and the like, but the lower limit of the temperature is preferably 30°C, more preferably 50°C. The upper limit of the temperature is preferably 200°C, more preferably 150°C. The lower limit of the heating time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, more preferably 300 seconds.

[Exposure process]
In this step, the organic resist film formed in the coating step (I-2) is exposed to radiation.

As the radiation used for the exposure, depending on the type of radiation-sensitive acid generator, quinonediazide-based photosensitizer and cross-linking agent used in the organic resist film forming composition, visible light, ultraviolet light, far ultraviolet light, X-ray, It is appropriately selected from electromagnetic waves such as γ-rays, electron beams, molecular beams, and particle beams such as ion beams. Of these, far ultraviolet rays are preferable, and KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F ₂ excimer laser light (wavelength 157 nm), Kr ₂ excimer laser light (wavelength 147 nm), ArKr excimer laser light. (Wavelength: 134 nm) or extreme ultraviolet light (wavelength: 13.5 nm etc., EUV) is more preferable, and KrF excimer laser light, ArF excimer laser light, EUV or extreme ultraviolet light is further preferable.

After the above exposure, heating can be performed to improve resolution, pattern profile, developability, etc. The heating temperature is appropriately adjusted depending on the type of the organic resist film forming composition used and the like, but the lower limit of the temperature is preferably 50°C, more preferably 70°C. The upper limit of the temperature is preferably 200°C, more preferably 150°C. The lower limit of the heating time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, more preferably 300 seconds.

[Development process]
In this step, the exposed organic resist film is developed. This development may be alkali development or organic solvent development. As the developing solution, in the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyl Diethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5 Examples thereof include basic aqueous solutions of diazabicyclo[4.3.0]-5-nonene and the like. An appropriate amount of a water-soluble organic solvent such as alcohols such as methanol and ethanol, a surfactant and the like can be added to these basic aqueous solutions. Further, in the case of organic solvent development, examples of the developing solution include various organic solvents exemplified as the solvent [B] of the above composition (I).

After the development with the above-mentioned developing solution, a predetermined resist pattern is formed by washing and drying.

[Chlorine gas contact process]
In this step, chlorine gas is brought into contact with the resist underlayer film using the resist pattern formed in the developing step (I) as a mask. As a result, the resist underlayer film in contact with chlorine gas becomes a film containing cobalt (II) chloride as a main component, and is soluble in a removing solution containing water or an organic solvent.

[Removal process]
In this step, the resist underlayer film in contact with chlorine gas is removed with a removing solution containing water or an organic solvent. As a result, the pattern of the resist underlayer film is formed.

Examples of the organic solvent include those listed as the organic solvent [b].

When the removing liquid (I) contains an acid, for example, a liquid containing an acid and water, a liquid obtained by mixing an acid, hydrogen peroxide and water, and the like can be mentioned. Examples of the acid include sulfuric acid, hydrofluoric acid, hydrochloric acid, phosphoric acid and the like. More specifically, the acid-containing removal liquid (I) is, for example, a liquid obtained by mixing hydrofluoric acid and water, a liquid obtained by mixing sulfuric acid, hydrogen peroxide and water, hydrochloric acid, or peroxide. Examples include liquids obtained by mixing hydrogen and water.

When the removal liquid (I) contains a base, examples thereof include a liquid containing a base and water, a liquid obtained by mixing a base, hydrogen peroxide and water, and the like, which is obtained by mixing a base, hydrogen peroxide and water. Liquids are preferred.

Examples of the base include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, Triethanolamine, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3] .0]-5-nonene and the like. Of these, ammonia is preferred.

The lower limit of the temperature in the removing step is preferably 20°C, more preferably 40°C, and even more preferably 50°C. The upper limit of the temperature is preferably 300°C, more preferably 100°C.

The lower limit of the time in the removing step is preferably 5 seconds, more preferably 30 seconds. The upper limit of the time is preferably 10 minutes, more preferably 180 seconds.

<Reversal pattern forming method>
The inversion pattern forming method includes a step of directly or indirectly forming an organic underlayer film on a substrate (hereinafter, also referred to as “organic underlayer film forming step (II)”) and a resist pattern directly or indirectly on the organic underlayer film. A step of forming (hereinafter, also referred to as “resist pattern forming step (II)”), a step of forming a reverse pattern forming film on the resist pattern (hereinafter also referred to as “reverse pattern forming film forming step”), And a step of forming a reverse pattern by removing the resist pattern (hereinafter, also referred to as a “reverse pattern forming step”). In the substrate manufacturing method, the composition (hereinafter, also referred to as “composition (II)”) described above as the coating film forming composition is used in the inversion pattern forming film forming step.

According to the inversion pattern forming method, since the composition (II) is used, a good inversion pattern can be formed.

The reversal pattern forming method includes a step of forming a resist intermediate film on the organic underlayer film formed by the organic underlayer film forming step (II) before the resist pattern forming step (hereinafter, referred to as "resist intermediate step", if necessary). (Also referred to as a film forming step)). May be further provided.

Hereinafter, each step included in the inversion pattern forming method will be described.

[Organic Underlayer Film Forming Step (II)]
In this step, an organic underlayer film is formed on the substrate. Examples of the substrate include the same substrates as those used in the coating step in the above-described method for manufacturing the substrate.

The organic underlayer film can be formed of an organic compound. As the above-mentioned organic compound, as a commercially available product, for example, "NFC HM8006" of JSR Corporation can be mentioned. The organic underlayer film can be formed by applying a composition for forming an organic underlayer film by a spin coating method or the like to form a coating film, and then heating.

The lower limit of the average thickness of the organic underlayer film formed is preferably 10 nm, more preferably 50 nm, further preferably 100 nm. The upper limit of the average thickness is preferably 1000 nm, more preferably 500 nm.

[Resist intermediate film forming process]
In this step, a resist intermediate film is formed on the organic underlayer film formed in the above organic underlayer film forming step (II). As the resist intermediate film, commercially available products such as “NFC SOG01”, “NFC SOG04”, and “NFC SOG080” (above, JSR Corporation) can be mentioned. Further, polysiloxane, titanium oxide, aluminum oxide, tungsten oxide, or the like formed by a CVD method can be used. The method for forming the resist intermediate film is not particularly limited, but for example, a coating method, a CVD method or the like can be used. Among these, the coating method is preferable. When the coating method is used, the resist intermediate film can be continuously formed after forming the organic underlayer film.

[Resist pattern forming step (II)]
In this step, a resist pattern is formed directly or indirectly on the organic underlayer film. Examples of the case of indirectly forming a resist pattern on the organic underlayer film include a case of forming a resist pattern on the resist intermediate film formed by the resist intermediate film forming step. Examples of methods for forming the resist pattern include known methods such as a method using a resist composition and a method using a nanoimprint lithography method.

[Reverse pattern forming film forming step]
In this step, a reverse pattern forming film is formed on the resist pattern. Specifically, in this step, the reverse pattern forming film is formed by applying the composition (II) onto the substrate on which the resist pattern is formed. In this case, the composition (II) is embedded in the gap between the resist patterns. Specifically, examples of the method for applying the composition (II) onto the substrate on which the resist pattern is formed include known methods such as spin coating, cast coating, and roll coating. In the above, it is preferable to provide a drying step after the composition (II) is embedded in the gap of the resist pattern. Although the drying means is not particularly limited, for example, the organic solvent [b] in the composition (II) can be volatilized by firing. The firing conditions are appropriately adjusted depending on the composition of the resin composition, but the firing temperature is usually 80 to 250°C, preferably 80 to 200°C. When the firing temperature is 80 to 180° C., the flattening step described later, particularly the flattening process by the wet etch back method can be smoothly performed. The heating time is usually 10 to 300 seconds, preferably 30 to 180 seconds. The thickness of the reverse pattern forming film obtained after drying is not particularly limited, but is usually 10 to 1000 nm, preferably 20 to 500 nm.

[Reversal pattern formation process]
In this step, the resist pattern is removed and an inverted pattern is formed.

Specifically, first, preferably, a flattening process is performed to expose the upper surface of the resist pattern. Next, the resist pattern is removed by dry etching or dissolution removal to obtain a predetermined inversion pattern.

By this inversion pattern forming process, it is possible to form a fine pattern with a high aspect ratio on a substrate, which is difficult with a normal lithography process. Thereby, a fine pattern can be transferred to the substrate.

As the flattening method used in the flattening process, an etching method such as dry etch back or wet etch back, or a CMP method can be used. Among these, the dry etch back method and the wet etch back method using a fluorine-based gas or the like are preferable at low cost. The processing conditions in the flattening process are not particularly limited and can be adjusted as appropriate.

Also, dry etching is preferable for removing the resist pattern, and specifically, oxygen-based gas etching, ozone etching, etc. are preferably used. Known devices such as an oxygen plasma ashing device and an ozone ashing device can be used for the dry etching. The etching processing conditions are not particularly limited and can be adjusted appropriately.

<Method for forming organic underlayer film pattern>
The inversion pattern formed by the above-described inversion pattern forming method can be used as, for example, a mask when patterning the organic underlayer film. In other words, the above-mentioned inversion pattern forming method can be suitably adopted as a pre-process of the organic underlayer film pattern forming method described later.

The organic underlayer film pattern forming method includes a step of etching the organic underlayer film using the inversion pattern formed by the above inversion pattern forming method as a mask (hereinafter, also referred to as “organic underlayer film pattern forming step”), After the chlorine gas is brought into contact with the inversion pattern, a step of removing the inversion pattern with a removing liquid containing water or an organic solvent (hereinafter, also referred to as “inversion pattern removing step”) is provided.

[Organic underlayer film pattern forming step]
In this step, the organic underlayer film is etched by using the inversion pattern formed by the above inversion pattern forming method as a mask. Examples of this etching method include dry etching and wet etching. The dry etching can be performed using a known dry etching apparatus. The source gas during dry etching depends on the elemental composition of the film to be etched, but is, for example, a fluorine-based gas such as CHF ₃ , CF ₄ , C ₂ F ₆ , C ₃ F ₈ or SF ₆ , Cl ₂ or the like. , Chlorine-based gas such as BCl ₃ , oxygen-based gas such as O ₂ and O ₃ , H ₂ , NH ₃ , CO, CO ₂ , CH ₄ , C ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , C A reducing gas such as ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , HF, HI, HBr, HCl, NO, NH ₃ , BCl ₃ or an inert gas such as He, N ₂ or Ar is used. It is also possible to use a mixture of these gases. Usually, a fluorine-based gas is used for dry etching of the resist intermediate film when forming the resist intermediate film, and an oxygen-based gas is preferably used for dry etching of the organic lower layer film.

[Reverse pattern forming film removal step]
In this step, chlorine gas is brought into contact with the inversion pattern and then removed with a removing liquid containing water or an organic solvent. By this step, the reversal pattern in contact with chlorine gas becomes a film containing cobalt (II) chloride as a main component and is soluble in a removing liquid containing water or an organic solvent, and thus is removed.

The removing solution used in this step is the same as the removing solution (I) in the removing step of the pattern forming method described above.

<Formation of damascene structure>
By coating the coating film forming composition on the patterned low dielectric insulating film, filling the pattern (wiring groove), and heating the coating film, the cobalt metal layer (wiring layer) is formed. Can be formed. A barrier metal film may be formed before applying the coating film forming composition. After forming the cobalt metal layer, a part of the cobalt metal layer is removed by chemical polishing (CMP) to expose and flatten the surface of the low dielectric insulating film. The coating conditions and the heating conditions can be the same as those of the coating process and the heating process in the above-described method for manufacturing the substrate.

An example will be described below. In addition, the following embodiments are examples of typical embodiments of the present invention, and the scope of the present invention should not be construed narrowly.

[Average film thickness]
The average thickness of the film was measured using an X-ray diffractometer (“SmartLab” manufactured by Rigaku Corporation).

<Preparation of coating film forming composition>
The [A] compound, [B] solvent and [C] other organic compound used for the preparation of the coating film forming composition are shown below.

[[A] compound]
Compounds (A-1) to (A-6) and (a-1) to (a-2): The structures of the respective compounds are represented by the following formulas (A-1) to (A-6) and (a-1) to It is shown in (a-2).

[[B] solvent]
B-1: Propylene glycol monoethyl ether B-2: Ethyl lactate B-3: n-Butyl alcohol B-4: Propylene glycol monomethyl ether acetate B-5: Ethylene glycol B-6: 1,2-butanediol B- 7: diethylene glycol B-8: triethanolamine B-9: water B-10: 2-hydrazinoethanol (compound represented by the following formula (B-10))
B-11: 1-hydroxy-2-propanone hydrazone (compound represented by the following formula (B-11))

[[C] Other Organic Compound]
C-1: Citric acid (compound represented by the following formula (C-1))
C-2: Ascorbic acid (compound represented by the following formula (C-2))
C-3: gallic acid (compound represented by the following formula (C-3))
C-4: Acetic acid hydrazide (compound represented by the following formula (C-4))
C-5: Methylcarbazate (a compound represented by the following formula (C-5))
C-6: Cyanoacetic acid hydrazide (compound represented by the following formula (C-6))
C-7: Salicylic acid hydrazide (compound represented by the following formula (C-7))

[Example 1]
18 parts by mass of (A-1) as a compound [A] and 2 parts by mass of (A-2) are mixed with 80 parts by mass of (B-1) as a solvent [B], and the resulting solution has a pore size of A 0.2 μm nylon syringe filter was used for filtration to prepare a coating film forming composition (J-1).

[Examples 2 to 24 and Comparative Examples 1 to 2]
The coating film forming compositions (J-2) to (J-24) and (j-) were operated in the same manner as in Example 1 except that the components and contents shown in Table 1 below were used. 1) to (j-2) were prepared. "-" in Table 1 indicates that the corresponding component was not used.

<Evaluation>
Regarding the prepared coating film forming compositions (J-1) to (J-24) and (j-1) to (j-2), storage stability, conductivity and embedding of the formed cobalt-containing film. The sex was evaluated by the following method. The evaluation results are shown in Table 2 below.

[Storage stability]
The storage stability of the coating film-forming composition was evaluated by the difference in coating property over time. The composition for coating film formation (T=0) immediately after the above-mentioned preparation was placed on a cobalt substrate using a spin coater (“MS-B200” manufactured by Mikasa Co., Ltd.) under conditions of 1,500 rpm and 30 seconds. After coating by the spin coating method, the obtained coating film was heated at 500° C. for 300 seconds in a nitrogen atmosphere using an RTA furnace (“QHC-P610CP” manufactured by ULVAC, Inc.). A cobalt-containing film was formed. Regarding the coatability, the formed cobalt-containing film was observed with an optical microscope, and "A" (good) was observed when no coating unevenness was observed, and "B" (bad) when coating unevenness was observed. evaluated. Further, the coating film composition for which the coating property was evaluated was stored at 25° C. for 7 days (T=7), the coating property was evaluated in the same manner as above, and evaluated in the same manner as above. Regarding the storage stability, the storage stability is good when both the coatability at T=0 and the coatability at T=7 are evaluated as “A” (good), and otherwise. Can be evaluated as having poor storage stability.

[Conductivity]
The composition for coating film formation immediately after the above preparation was applied onto a silicon substrate by a spin coating method using a spin coater (“MS-B200” manufactured by Mikasa Co., Ltd.). Next, using an RTA furnace (“QHC-P610CP” manufactured by ULVAC, Inc.) in a nitrogen atmosphere, the sample was heated at 500° C. for 300 seconds and then cooled at 23° C. for 60 seconds to give an average thickness of 200 nm. A cobalt-containing film was formed to obtain a silicon substrate with a cobalt-containing film. The resistivity of the cobalt-containing film in the silicon substrate with the cobalt-containing film was measured using a resistivity measuring device (“Σ-5” manufactured by Enpies Co., Ltd.) by the direct current 4-probe method. The electrical conductivity is “S” (extremely good) when the specific resistance is 25.0 μΩ·cm or less and “A” (good) when the specific resistance is more than 25.0 μΩ·cm and 50.0 μΩ·cm or less, When it was larger than 50.0 μΩ·cm, it was evaluated as “B” (poor).

[Embedding]
A spin coater (“MS-B200” manufactured by Mikasa Co., Ltd.) was applied to the prepared coating film-forming composition on a silicon substrate on which a line-and-space pattern having a depth of 400 nm and a width of 45 nm was formed. It was used and was coated by the spin coating method. Next, using an RTA furnace ("QHC-P610CP" manufactured by ULVAC, Inc.) in a nitrogen atmosphere, after heating at 500°C for 300 seconds and then cooling at 23°C for 60 seconds, the line pattern portion A cobalt-containing film having an average thickness of 50 nm was formed to obtain a silicon substrate with a cobalt-containing film. The cross-sectional shape of the silicon substrate with the cobalt-containing film was observed with a scanning electron microscope (“SU8220” manufactured by Hitachi High-Technologies Corporation) to evaluate embeddability. The embeddability was evaluated as "A" (good) when the cobalt-containing film was buried to the bottom of the space pattern and "B" (bad) when the cobalt-containing film was not buried to the bottom of the pattern. ..

From the results in Table 2 above, it can be seen that the coating film forming compositions of the examples are excellent in storage stability and also in conductivity and embedding property of the cobalt-containing film to be formed.

The coating film forming composition of the present invention has excellent storage stability. According to the method for producing a substrate of the present invention, by using the coating film forming composition, a cobalt-containing film having excellent conductivity and embedding property can be formed. Therefore, these can be suitably used in forming a cobalt-containing film in the fields of semiconductors, battery materials and the like.

Claims (10)

1. A cobalt-containing compound having no cobalt-carbon bond,
   A coating film-forming composition containing a solvent.
2. The solvent includes an organic solvent,
   The coating film-forming composition according to claim 1, wherein the organic solvent contains an alcohol solvent.
3. The coating film forming composition according to claim 2, wherein the alcohol solvent is a monoalcohol, a polyhydric alcohol partial ether, a lactic acid ester, a hydrazino alcohol, a hydroxyketone hydrazone, or a combination thereof.
4. The coating film forming composition according to claim 2 or 3, wherein the content ratio of the alcohol solvent in the organic solvent is 50% by mass or more.
5. The coating film formation according to any one of claims 1 to 4, wherein the cobalt-containing compound is a cobalt salt of nitric acid, sulfuric acid or carboxylic acid, a complex having cobalt and a ligand, or a combination thereof. Composition.
6. The coating film forming composition according to any one of claims 1 to 5, wherein the content ratio of the cobalt-containing compound in all components other than the solvent is 50% by mass or more.
7. The coating film-forming composition according to any one of claims 1 to 6, which is for pattern formation.
8. The composition for forming a coating film according to any one of claims 1 to 6, which is for forming a reverse pattern.
9. Comprises a step of directly or indirectly coating the composition on the substrate,
   A method for producing a substrate, wherein the composition contains a cobalt-containing compound having no cobalt-carbon bond and a solvent.
10. The method for manufacturing a substrate according to claim 9, further comprising: a step of heating the coating film formed by the coating step.